title: High altitude impairs in vivo immunity in humans.
abstract: The aim was to assess the effect of high altitude on the development of new immune memory (induction) using a contact sensitization model of in vivo immunity. We hypothesized that high-altitude exposure would impair induction of the in vivo immune response to a novel antigen, diphenylcyclopropenone (DPCP). DPCP was applied (sensitization) to the lower back of 27 rested controls at sea level and to ten rested mountaineers 28 hours after passive ascent to 3777 m. After sensitization, mountaineers avoided strenuous exercise for a further 24 hours, after which they completed alpine activities for 11-18 days. Exactly 4 weeks after sensitization, the strength of immune memory induction was quantified in rested mountaineers and controls at sea level, by measuring the response to a low, dose-series DPCP challenge, read at 48 hours as skin measures of edema (skinfold thickness) and redness (erythema). Compared with control responses, skinfold thickness and erythema were reduced in the mountaineers (skinfold thickness,-52%, p=0.01, d=0.86; erythema, -36%, p=0.02, d=0.77). These changes in skinfold thickness and erythema were related to arterial oxygen saturation (r=0.7, p=0.04), but not cortisol (r<0.1, p>0.79), at sensitization. In conclusion, this is the first study to show, using a contact sensitization model of in vivo immunity, that high altitude exposure impairs the development of new immunity in humans.
authors.affiliation: Extremes Research Group, School of Sport, Health and Exercise Sciences, Bangor University, Bangor, Gwynedd, United Kingdom. s.j.oliver@bangor.ac.uk
authors.forename: Samuel J
authors.initials: SJ
authors.lastname: Oliver
authors.forename: Jamie H
authors.initials: JH
authors.lastname: Macdonald
authors.forename: Adam D
authors.initials: AD
authors.lastname: Harper Smith
authors.forename: Justin S
authors.initials: JS
authors.lastname: Lawley
authors.forename: Carla A
authors.initials: CA
authors.lastname: Gallagher
authors.forename: Umberto
authors.initials: U
authors.lastname: Di Felice
authors.forename: Neil P
authors.initials: NP
authors.lastname: Walsh
mesh_terms: D000217:Acyltransferases / Q000187:drug effects / Q000276:immunology; D000279:Administration, Cutaneous; D000328:Adult; D000531:Altitude; D015415:Biomarkers / Q000097:blood; D003430:Cross-Sectional Studies; D003521:Cyclopropanes / Q000008:administration & dosage / Q000276:immunology* / Q000494:pharmacology; D003877:Dermatitis, Contact / Q000097:blood / Q000276:immunology*; D029721:Drosophila Proteins / Q000187:drug effects / Q000276:immunology; D004890:Erythema / Q000139:chemically induced / Q000276:immunology; D005260:Female; D006241:Haptens / Q000008:administration & dosage / Q000276:immunology* / Q000494:pharmacology; D006801:Humans; D008297:Male; D009051:Mountaineering / Q000502:physiology*; D010100:Oxygen / Q000097:blood
chemical_list: D015415:Biomarkers; D003521:Cyclopropanes; D029721:Drosophila Proteins; D006241:Haptens; C446031:rasp protein, Drosophila; D000217:Acyltransferases; C029402:diphenylcyclopropenone; D010100:Oxygen